The invention relates to a picture pick-up and display system comprising an image intensifier for intensifying radiation from a scene to be picked up, for which purpose the image intensifier has a radiation entrance surface and a radiation exit surface, an image sensor for picking up on a picture pick-up surface a picture corresponding to the scene on the radiation exit surface and for supplying a line and field-sequentially generated picture signal corresponding thereto, an optical coupling system arranged between the radiation exit surface of the image intensifier and the picture pick-up surface of the image sensor for adapting the shape of the radiation exit surface to that of the picture pick-up surface, a signal correction device for compensating the adaptation of the optical coupling system by supplying a corrected picture signal, and a display device provided with a display screen for displaying a picture corresponding to the scene whilst applying the corrected picture signal to the display device. The invention also relates to a picture pick-up device suitable for said system.
Such a device including the image intensifier which is, for example, further operative as a radiation converter for converting invisible radiation into visible light as radiation may be used, for example, for X-ray pictures, for observation in the infrared or ultraviolet radiation range etc. The image sensor then operates as an opto-electronic sensor. If the image sensor is sensitive to radiation other than light, the image intensifier/radiation converted may be constructed to convert any type of radiation into the specific radiation to which the image sensor is sensitive. An image intensifier without radiation conversion can be used when picking up a scene having a light level which is too low for the image sensor.
When picking up pictures, a problem occurs if the shape of the radiation exit surface of the image intensifier is not equal to that of the picture pick-up surface of the image sensor. Surface shapes which are circular, rectangular, square or ellipsoidal are mentioned as examples. The optical coupling system ensures the adaptation of the shape, but the result upon direct display of the picture signal would be the display of a distorted picture. Before the picture is displayed, the distortion is compensated electronically by means of the signal correction device so that a picture corresponding to the scene results on the display screen.
If the image intensifier and the image sensor are both in the form of a vacuum tube, the said problem does not occur or hardly occurs because the radiation exit surface and the picture pick-up surface generally have a circular shape. The problem does occur in the combination of an image intensifier in the form of, for example, a vacuum tube and an image sensor in the form of a solid state sensor, with the image intensifier having a circular radiation exit surface and the sensor often having a rectangular picture pick-up surface. The rectangular shape particularly conforms to the shape of television display screens for the display of the line and field-sequentially formed picture. Examples of the aspect ratio of the rectangular shape are 3 to 4, 3 to 5, 9 to 16, etc. The line and field scanning directions are conventionally in the direction of the length and the width, respectively, of the rectangle.